John Key made his fortune as a currency trader
John Key made a fortune as a currency trader before returning to New Zealand to pursue his political ambitions.
Critics said that with only six years' experience as an MP, he did not have the experience to successfully lead New Zealand as prime minister.
But after rejuvenating the centre-right National Party, he has swept to power in an election dominated by change.
"In their hundreds and thousands across the country they have voted for change," he said after his victory.
John Key was born in Auckland and brought up by his mother after his father died when Mr Key was only six years old.
After training as an accountant, he became a currency trader in New Zealand, before moving to Singapore and then London.
During a successful, and highly-paid career, he earned the nickname "smiling assassin" for his ability to remain cheerful while making staff cuts.
In returning home and running for political office he "fulfilled a long-held ambition".
He won the Helensville seat in 2002 - and again in 2005, having increased his majority eightfold.
Mr Key, who is married with two children, was elected leader of the party in 2006.
Analysts says he has forced National into the political middle, accepting Labour policies such as the anti-nuclear law and the deployment of troops to Afghanistan.
But his pledge to lower taxes and get tough on criminal gangs also appealed to voters.